options to skip rakefile

By default we load the rakefile and run the resque:pool rake task, because that follows the instructions in the resque README. We can also provide the ability to run Resque::Pool.run directly, from inside the resque-pool daemonizing script.

--init, -i <s>: Preload ruby script to initialize resque-pool
     --no-rake: Run without loading Rakefile or resque:pool task

to be run like so:
resque-pool -d -e production -i config/resque-pool-init.rb --no-rake

and config/resque-pool-init.rb might look like so:
require File.expand_path('environment', File.dirname(FILE))
# setup resque failure backend
# close any sockets or files in pool master
ActiveRecord::Base.connection.disconnect!
# and re-open them in the resque worker parent
Resque::Pool.after_prefork do |job|
ActiveRecord::Base.establish_connection
end

Start with the resque-pool daemonizing script and its existing --init handling. Trace how the Rakefile and resque:pool task are loaded, then verify that --no-rake can invoke Resque::Pool.run while an init script still loads and configures the environment.